this gen 2 light is gonna drive me nuts

gen two light stays off at idle and both alternators are producing 14v at idle. light goes on and off as you drive down the road. I have no idea where to start with this. I've checked all connections they all seem tight and all grounds are on. any help would be appreciated or where to start from here. I'm debating switching it to 12v system but I wanna keep it original if I can.

Did you clean all the connections to the alternator?

Did you clean the grounds and reconnect or just tighten? Corrosion can prevent good contact.

There is a ground in the cab behind the dash near the door that is hard to see. Did you clean that one?

Did you have the alternator tested?

Loose or worn belt?

Just tossing out ideas, and this site is a great resource. Hope you get it sorted. Keeping it original makes it easier to diagnose future issues.

Rebuild your alternators.

Voltage is but one quality of alternator health. There are 9 diodes in the alternator which can fail and cause unsteady voltage. I've had failure of one, it was a dead short and desoldered itself but not before taking out one alternator belt.

On a cold start, you can expect 80 amperes just off idle speed. The torque required to generate that much current is right at the limit of the belt. If the belt is old and glazed, you might not hear it.

I second the rebuild recommendation. And double check your high idle solenoid for 850 RPM. This will greatly help offload the alternators after a cold start so the belts aren't burned.

Did you swap the relay for the gen with the voltage gauge relay and did that make a difference?